Design of Sub-microwatt Oscillators with Temperature Compensations
Date Issued
2014
Date
2014
Author(s)
Lee, Ya-Shan
Abstract
This thesis consists of two parts. The first part aims to design a submicrowatts and low temperature coefficient (TC) relaxation oscillator. In this oscillator, the transistors in the subthreshold region, the current-mode comparator, and the current-starving inverters are used to reduce the power of the relaxation oscillator. The low TC current reference is realized with different gate-oxide thickness mosfets. Besides, we developed the curvature current source and the piecewise current source to compensate the TC of the oscillator. This oscillator is fabricated in a 0.18-μm CMOS process and its power consumption is 410nW with a supply voltage of 1.2V. The measured average TC is 49.7ppm/°C for the temperature of -20~80°C. The calculated FOM1, FOM2 and FOM3 are 124.2dB, -136.7dB and 101dB, respectively.
The second part implements a resistor-free oscillator. In this oscillator, we proposed the transistors in the linear region to replace passive resistors. The low TC
current reference is realized by PTAT and CTAT current and the voltage generator is implemented with different gate-oxide thickness mosfets. Besides, the piecewise curvature current is used to release the temperature variations. For the 1.6MHz oscillator, its power consumption is 631nW with a supply voltage of 1V. The average temperature coefficient is 66ppm/°C for the temperature of -20~80°C, and the calculated power FOM1, FOM2 and FOM3 are 124.1dB, -155.2dB and 114dB,
respectively.
Subjects
低功耗
振盪器
溫度補償
Type
thesis
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